The present invention concerns a method for manufacturing a tag which encompasses an antenna or a coil. The invention further relates to an apparatus for executing the method i, and a tag encompassing an antenna or coil or a corresponding chip card.
Chip cards or identification cards encompassing an antenna or a coil or similar small-scale assemblies such as for instance tags, transponder units and the like, are known in a multiplicity of embodiments. They generally serve to receive wireless information and, in some cases, to process it, but also to transmit information, for instance concerning the location, the properties of the objects connected to it and similar information (back) to the appropriate receivers.
In addition to many other areas of application, the use of so-called tags is becoming increasingly important, for instance for baggage sorting at airports, where hundreds of thousands of suitcases are conveyed to their correct destinations using automated transportation systems, as well as for postal items, where they make automated sorting possible. To achieve this, specific address codes are entered into the tags and the tags are then attached to the particular goods, with the tags wirelessly conveying relevant information to any inquiry units along the automated transportation route, so that for instance, switching units or distribution belts or sorting devices along the transportation route can respond.
In order to receive or transmit such information wirelessly, such tags, as they shall be known representatively for all other assemblies containing antennas or coils, chip or identification cards, transponders or the like, all require coiled, wound or meandering lengths of wire in some helical form for receiving or transmitting electromagnetic signals, which are usually in a digitally encoded form.
However, when attaching or applying such coils or antennas to each substrate, there are certain problems that significantly increase the cost of such tags that are now required in their millions. This means that the commonly used etching technique, with which single coil connections can be applied to chip-card foil substrates (EP 0 481 776 A2), requires numerous additional processing steps. In particular, these involve the application of photoresist to vapour-deposited or otherwise applied conductive layers, then their exposure using masks and the removal of intermediate layers by means of etching, all of which make the production of such tags considerably more expensive, especially when one considers the large number of units common in this field.
Turns of the coil are also known that are basically wire windings attached in the form of a continuous winding on a synthetic substrate with the aid of complex wiring and cutting machines, whereby the synthetic substrate is heated thermally at the same time in such a way that the turns of the wire bond at least partially with the heated synthetic substrate material and in this way retain their shape at least until further layers can be applied (U.S. Pat. No. 3,674,602, international PCT application WO 95/26538).
Both methods of attaching the wire are complicated as well as time-consuming, with WO 95/26538 also proposing that the coil wire be connected to the first terminal pad of a chip located on the chip card at the same time as it is being laid. Then the coil wire is laid to create the coil and finally the running end of the coil wire is connected to a second terminal pad on the chip, whereby the wire is connected at least partially to the substrate during the laying of the coil wire as a consequence of the substrate being heated.